Measuring environmental tritium with the Hidex ULLA
19/02/2024
The André E. Lalonde AMS Laboratory in Canada is the first site in North America to be using the new ultra-low level counter, superseding the QUANTULUS 1220
The launch of the Hidex ULLA last year has reintroduced ultra-low level analysing to liquid scintillation counting following the absence of a similar instrument for many years. The André E. Lalonde Accelerator Mass Spectrometry (AMS) Laboratory at the University of Ottawa is the first site in North America to use the Hidex ULLA, where it measures low levels of environmental tritium.
The lab is Canada's national centre for environmental radioisotope analysis and research in environmental sciences, health sciences, and nuclear energy. The facility measures trace concentrations of radioisotopes and other rare elements in the environment from both natural sources and human activities.
Counting below conventional detection levels
Explaining the lab’s work and how Hidex ULLA is used, Tritium & Noble Gas Laboratory Manager Anthony Lapp said, “We’re not concerned with high levels of tritium like what you might find at operating nuclear sites which can be performed by traditional LSC. We’re measuring very low levels of radionuclides in the environment, specifically tritium, below conventional detection limits of 1 Bq per litre. Most of our analyses are performed after electrolytic enrichment so we’re able to concentrate the tritium from around 250 ml to 10 ml, allowing us to measure samples as low as 0.1 Bq per litre and that’s when we measure them using the Hidex ULLA.”
The André E. Lalonde Accelerator Mass Spectrometry Laboratory at the University of Ottawa with Anthony Lapp (inset).
“We wanted a second ultra-low level counter for increased throughput, which was hard to find since the discontinuation of the QUANTULUS.”
The Hidex ULLA achieves ultra-low background with heavy passive lead shielding and geometrically optimal active guards surrounding the detector with three PMTs.
Anthony said, “We’ve been using a 1220 QUANTULUS for a while, but it’s aging and there was nothing else available until the Hidex ULLA came along. Others claim you can use a conventional counter, but nothing is going to substitute half a tonne of lead or burying it five stories underground, which we can’t do here. We wanted a second ultra-low level counter for increased throughput, which was hard to find since the discontinuation of the QUANTULUS.”
“The Hidex ULLA gives us higher efficiencies, better results, lower uncertainties.”
The Hidex ULLA hasn’t just reintroduced ultra-low level counting, it’s also improved on the previous generation of instruments with more modern components, including three PMTs instead of the traditional two for Triple to Double Coincidence Ratio (TDCR) featured in all Hidex counters. TDCR automatically calculates counting efficiency and eliminates the need for an internal radiation source.
Anthony said, “The Hidex ULLA gives us higher efficiencies, better results, lower uncertainties. All that lead shielding is needed to lower the background and produce lower uncertainties in the results. It has a lot of innovations and conveniences. The antistatic feature to deionise the sample vials is helpful to negate false counts or higher background, and the active guard around the triple PMTs helps give greater counting efficiencies. It’s been very exciting to have the Hidex ULLA installed and working.
“I was first introduced to Hidex in 2015 at a hydrology symposium at the IAEA in Vienna. Trying to get support from other vendors can be very frustrating sometimes, but we’ve had very good assistance from Hidex. Everybody there seems genuinely interested in creating a good product and in seeing their instrument perform well. They’re open to feedback and they’re in touch with their user base, it makes me want to come back to them.”
Find out more
The sale, service, and support of the Hidex ULLA at the University of Ottawa was carried by Gamble Technologies (GTL), Hidex’s Canadian distributor and partner based in Mississauga, whose engineers carried out the installation and commissioning onsite. As the US and UK distributor for Hidex, LabLogic offers similar customer service and support.
You can learn more about the Hidex ULLA by clicking the button below to speak to a product specialist directly.